Weather It Is (Winter Storm Warning/Extreme Cold)

 Good Morning:

As discussed in our "Israel Winter Weather" group, forecast conditions have trended towards both snow and extreme cold.  In areas that normally see snow during winter storms (including Jerusalem), this combination will create impassable driving conditions late Wednesday into Thursday, if not later where frozen precipitation remains on the roads. Snow accumulations are potentially between 10 and 20 cm in the Jerusalem area, depending on elevation.  Lighter snow amounts are expected in the north.

In our previous storm, the forecast trended away (towards lower probability) as we approached the storm event, leaving us with just extreme cold.  But, we've been watching this potential event for several days, and the trend towards a deeper 500 mb trough, and more prolonged and heavy precipitation has continued to this day (Tuesday).

Some important details: this storm should bring even colder weather than our last.  More importantly, later in the afternoon and evening, high relative humidity in the "Dendritic" zone (-12 to -18 Celsius), will lead to rapid formation of large snowflakes. These snowflakes will form as moisture from the sea overruns the cold air at the surface and within the mountain ridges.  The snow will accumulate quickly, closing roads, so travel will probably be impossible from late afternoon Wednesday into Thursday. The heaviest snow should fall in the late afternoon and evening hours. The deep freeze should last into Friday morning.

Be Safe,

Barry Lynn